Current practice is generally to employ different networks for telephone and data applications. A business may have a wired telephone system connected to a Private Branch Exchange (PBX) and a separate network of LAN segments connected together over a broadband backbone. This means duplication of cabling, leading to higher physical complexity and cost. Data traffic is by its nature fundamentally different from voice traffic due to its bursty nature and the fact that it does not need to be delivered in a time critical fashion. A computer file can be transferred as bandwidth becomes available, and the file can still be correctly assembled at the receiving end. This is not true of voice traffic, which must be delivered in a time sensitive manner in order to be intelligible to the receiver.
New ATM (Asynchronous Transfer Mode) technology will eventually allow the complete integration of voice and data. The migration to ATM, however, requires a complete replacement of existing systems and therefore is extremely expensive for organizations with existing PBX systems.
A need arises for a technology that can provide a painless migration from existing dual-wired systems to a more integrated system without making existing equipment obsolete and thus wasting existing capital investment.